Computational investigation of different effects on the performance of the Ranque-Hilsch vortex tube

The Ranque-Hilsch vortex tube is a simple device with no moving parts and no mechanical operations. This device separates the inlet air into two distinctive regions; an outward high temperature region and an inner low temperature one. A computational study of the tube is presented in this article using an axisymmetric model using the ANSYS Fluent (R) software whose results showed good agreement with the experimental measurements. The effects of the tube length to diameter ratio and the cold orifice size on the performance of the tube were investigated. The results showed that length to tube diameter ratio (LID) affects the performance of the tube, and that this effect changes when operating the tube at different cold mass fractions. The results showed also that the maximum cooling occurs at the lowest cold orifice to tube diameter ratio (d(c)/D) at the lowest cold mass fraction (mu(c)) possible while the maximum heating occurs at the highest d(c)/D at the highest mu(c) possible. Secondary circulations were investigated when operating at low d(c)/D values. In order to enhance the cooling capabilities of the tube fins were added to the tube to enhance the natural convection on the wall of the tube. (C) 2015 Published by Elsevier Ltd.